Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Biology

Supervisor

Lindo, Z.

Abstract

Short-term climate perturbations affect both predator and prey species that comprise soil communities, and alter carbon flux. I used a mesocosm experiment to model the effects of experimentally-imposed temperature and moisture conditions that simulate potential future conditions during climate perturbations, on peatland soil food web flux and soil carbon sequestration after three-weeks of experimentally imposed conditions, and then again after an additional three-week recovery under control conditions. I compared system resistance and resilience, and modelled carbon (C) and nitrogen (N) fluxes throughout the mesocosm experiment. There was a lack of resistance of the soil food web to perturbation shown by changes in total faunal abundance under imposed soil moisture treatments. System resistance and resilience are important concepts to understand as climate change threatens C storage in boreal peatlands, a globally significant C store.

Summary for Lay Audience

Carbon (C) makes up the substrate, habitat, and diet of soil-dwelling organisms. Therefore, soil food web C storage is defined by the total amount of C consumed by soil fauna less the total C released to the atmosphere by the respiration of soil fauna. Short-term changes in temperature and soil moisture affect the storage of C in soils. Boreal peatlands are a wetlands ecosystem found across Canada that play an especially important role in global C storage. The goal of my thesis was to determine the effects of potential future temperature and soil moisture conditions on the total number of soil fauna, the total amount of C consumed by soil fauna, and the total C released to the atmosphere by the respiration of soil fauna before the simulated short-term event, immediately following the event, and then following a subsequent recovery period under control conditions in peat-soils collected from White River, Ontario. Overall, the total number of soil fauna tended to decrease following the simulated event, and this was driven by imposed soil moisture treatments. The total number of fauna did not increase following the recovery period, and this was most noticeable in the number of fungal-feeding soil fauna. System resistance and resilience are important concepts to understand as climate change threatens C storage in boreal peatlands, a globally significant C store.

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